The most important reason for having a properly adjusted head restraint is to

الهدف الرئيسي من وجود مثبتات للرأس مثبتة بإحكام هو

Explanation: The restraint should be adjusted so that it gives maximum protection to the head and neck. This will help in the event of a rear-end collision.

Category: Arabic - Safety and Your Vehicle

References: The Official DVSA Guide to Driving: Section 3, Highway Code: Rule 97